Example of inlined datetime comparators

comparators.py

import enum
import datetime

import pydantic


class Comparator(enum.Enum):
    LT = "<"
    GT = ">"
    EQ = "="
    NE = "~"


class ComparatorDatetime(pydantic.BaseModel):
    timestamp: datetime.datetime
    comparator: Comparator

    @classmethod
    def __get_validators__(cls):
        yield cls._validate_format

    @classmethod
    def _validate_format(cls, value):
        return cls.construct(
            timestamp=datetime.datetime.fromisoformat(value[1:]),
            comparator=Comparator(value[0]),
        )


class MyModel(pydantic.BaseModel):
    ff: ComparatorDatetime


model = MyModel(ff=">2020-11-20T00:00:00")

print(model)